Believed to be the personification of Lady Luck in many cultures, due to their colorful and vibrant appearance, the seven-spotted ladybugs (or “Ladybirds” as they are known in some parts of the world) are an important component of the ecosystem. Widely available throughout Europe and North America, they offer immense help to farmers, eating a large number of plant-eating pests. Its scientific binomial nomenclature is Coccinella septempunctata. One of the more visually appealing species of beetle, the ladybug is named after the seven black spots on its chitinous exoskeleton. The hardened forewings (elytra) are red, giving the seven-spotted Ladybird its distinguishing color.
The Coccinella septempunctata derives its name from the Latin “Septem” (meaning Seven) and “Punctus” (meaning Spot). The ladybug belongs to the largest order in the entire Kingdom Animalia- Coleoptera, or the order of the beetle. It is a member of the Coccinellidae, a large family of small beetles. The size of the Coccinellidae ranges from 0.8 to 18 mm. The associated genus is Coccinella. Some entomologists argue that the ladybug or Ladybird should not be placed under the category of true beetles, due to several distinct properties and characteristics.
The length of a full-grown seven-spot ladybird varies from 7.6 to 10.0 mm. The bright colors combined with the distinctive spots make them rather unappealing to predators similar as Spanish Fly. Like most other beetles, the ladybirds secrete a fluid when attacked or under stress. This defensive fluid, known as reflex blood, is rich in the alkaloid Adaline which gives them a very foul taste. Ladybirds have the ability to synthesize toxic alkaloids such as N-oxide coccinelline and precoccineline. The toxicity of a single specific ladybird is indicated by the size of the spots and coloration. A funny and interesting fact to note is that when the seven-spot Ladybird feels afraid or threatened, it can play dead and secrete the defensive fluid simultaneously. These beetles also have around 11 segments in their antennae, and their toes are segmented into four different parts.
Habitat and Distribution
Due to the resourceful eating habits of the Ladybird, they can be found spread across all the continents of the world, except South America and Antarctica. The seven-spotted Ladybird can easily be found throughout Europe- including the eastern part of Russia, Belarus, Moldova, Siberia, and the Caucasus.
They can also be found through the tropical African nations and Asian countries such as India, Pakistan, Nepal, Japan, China, Mongolia, North, and South Korea. The species spread by natural dispersion in North America after it was artificially introduced in 1973. These days, the Ladybird is common from New York and Connecticut to Oklahoma, Georgia, and Delaware.
Though mostly found outdoors, the ladybirds may also enter your home. Their preference is generally old and light-colored homes, which are more likely to provide the warmth that they seek. They are hard to get rid of, as the pheromones secreted attract other ladybugs. But there is no need to fear, as ladybugs are not harmful to the human population, save the harlequin ladybirds of England which are a severely invasive species.
The seven-spotted Ladybird generally lays her eggs near places with a higher density of aphids. The young larvae have chemical footprints which the females may trace when deciding where to lay her eggs. Other than that, the ladybirds are found over vast steppe lands and forests.
Ladybirds have a voracious appetite, and their primary diet includes small aphids. For the ones left wondering, aphids are tiny insects which feed on the sap of plants and trees, including greenfly and blackfly. They belong to the superfamily Aphidoidea.
They also feed on Thysanoptera (Thrips), Aleyrodidae (whiteflies), spider mites, ticks, and fleas. Their diet includes the eggs and larvae of Psyllidae (jumping plant lice) Cicadellidae (leafhopper), specific beetles, and butterflies. In addition to various pests, the ladybirds like to eat pollen and nectar.
According to recent research, the larvae of several species of ladybirds are cannibals, eating one another while growing up. This cannibalism is also common in several other ladybirds.
The lifecycle of a ladybird consists of 4 stages: egg, larvae, pupae, and adult. The ladybirds lead a busy lifecycle.
- Stage 1
- The ladybirds may lay eggs more than once in a year. The number varies from species to species. The number of eggs in a single batch may exceed 30, and is generally less than 40. The eggs are yellow or orange in color. The incubation period is usually around 4-10 days.
- Stage 2
- The larvae stage is for a period of 3 to 6 weeks. The generally grey larvae may vary in color (buff and brown are also found at times). The spots found are mottled. During this period, the larvae shed their skin 4-5 times. They then cling to a stem/leaf and transform into pupae.
- Stage 3
- The pupal stage generally lasts up to two weeks. During this stage, the larvae undergo a series of changes inside the pupae. It slowly turns into a ladybird in a process known as the metamorphosis.
- Stage 4
- The final stage in the life of a ladybird is the fully-grown adult stage. During the first few hours after coming out of the pupal stage, the exoskeleton is bright yellow in color. Through the course of the next hours, the elytra harden, giving the seven-spotted ladybird its distinctive appearance.
Use as Biological Pest Control
Ladybird’s eating habits make them ideal candidates for biological pest control. They have been repeatedly used this way in various parts of the United States of America. Most of a ladbird’s diet is heavily based on farming pests like aphids and other small insects. The useful nature of the ladybirds, combined with its attractive appearance, has helped it to become the Official State Insect in 5 different states of the USA: Delaware, Massachusetts, New Hampshire, Ohio, and Tennessee.
Predators and Other Threats
Despite having good natural defense mechanisms, the Ladybird does have some predators and natural enemies. The ladybirds are heavily infested with parasitic mites, which may cause STDs among the ladybirds. The mites generally live on the host female termites and may transfer during the period of mating to another male. Natural predators include birds like swifts, swallows, and some spiders. Additional threats include rival ladybird species, which are often cannibalistic in nature.